Journal of Risk and Uncertainty最新文献

This article reviews economic studies based on data from high income countries published from 2007 to early 2024 to address three questions: (1) How accurate are subjective beliefs, mainly measured by subjective probabilities, compared to their objective counterparts? Objective evidence comes from another source (e.g., life table, empirical study, expert opinion), or subsequent realizations of beliefs elicited at baseline. (2) How are subjective beliefs determined? (3) Do subjective beliefs affect health behaviors? Several domains are included: survival, and health behaviors—smoking, alcohol consumption and impaired driving, preventive care, diet, and COVID-19 precautions. Results on a single domain, (e.g., survival), do not generalize to, e.g., COVID-19 results. Subjective probabilities embody private information (e.g., self-assessed health, parent longevity). However, individuals seem insufficiently informed about population-level probabilities. There is no systematic overestimation or underestimation of objective probabilities. Several determinants of beliefs are identified (demographic characteristics, education, cognition, current self-assessed health, health histories), but evidence on underlying mechanisms is lacking, how determinants, (e.g., education), affect beliefs. Subjective beliefs, even with substantial noise, often affect health behaviors. Given prior evidence that beliefs are influenced by health shocks, this article reviews research on effects of health shocks on health behaviors. A major health shock to an individual—a new diagnosis (e.g., diabetes) or a serious adverse health event (e.g., heart attack), by changing subjective probabilities leads to some healthier behaviors, however, sometimes only temporarily. Behaviors may also be influenced by utility loss following a health shock, e.g., learning about pecuniary and non-pecuniary costs of hospitalization.

We design and implement lab experiments to evaluate the normative appeal of behavior arising from models of ambiguity-averse preferences. We report two main empirical findings. First, we demonstrate that behavior reflects an incomplete understanding of the problem, providing evidence that subjects do not act on the basis of preferences alone. Second, additional clarification of the decision making environment pushes subjects’ choices in the direction of ambiguity aversion models, regardless of whether or not the choices are also consistent with subjective expected utility, supporting the position that subjects find such behavior normatively appealing.

We use natural experiments in Haiti and Denmark to test recent theoretical predictions about how agents react to random events. Using player-level administrative data, we find that the average lottery player avoids numbers that recently won (the gambler’s fallacy). A small subset of players in each country exhibit the hot hand fallacy, and bet recent winners. We find no evidence of ‘streak switching,’ in which beliefs switch from the gambler’s fallacy to the hot hand fallacy as winning streaks grow. Follow-up survey data in Haiti indicate that almost all lottery players believe that some numbers are more likely to win than others, and that recent winning history is an important factor in subjective beliefs about numbers’ win probabilities.

The formation of economic preferences in childhood and adolescence has long-term consequences for life outcomes. We study in an experiment how both birth order and siblings’ gender composition are related to risk, time, and social preferences. We find that second-born children are typically less patient, more risk-tolerant, and more trusting. However, siblings’ gender composition interacts importantly with birth order effects. Second-born children are more risk-taking only with same-gender siblings. In mixed-gender environments, children seem to identify with the gender stereotype that boys are much more willing to take risks than girls, irrespective of birth order. For trust and trustworthiness, birth order effects are larger with mixed-gender siblings. Only for patience, siblings’ gender composition does not matter.

Reference-dependence has become a widely established phenomenon in decision making under risk, not only for monetary outcomes but also for other outcomes, e.g., related to health. However, when the prospects involve risk about timing (the time of receipt of outcomes), rather than the outcomes themselves, much less is known about reference-dependence. This study extends discounted utility to incorporate reference-dependence and is the first to test it in timing prospects. We are also the first to estimate the probability weighting function for timing prospects. For both timing and outcome risk tasks, we replicate the typical fourfold pattern of risk attitudes: risk seeking for low-probability gains, risk aversion for high-probability gains, risk aversion for low-probability losses and risk seeking for high-probability losses. In other words, we find substantial pessimism with regard to high probabilities in the gain domain and low probabilities in the loss domain, and probabilistic optimism for low probabilities in the gain domain and high probabilities in the loss domain. Furthermore, we report loss aversion for outcome risks, while for timing risks, we find the opposite result, which we term earliness seeking. In sum, we find substantial empirical support for reference-dependent discounting. Our results show that psychological biases are also important when timing is risky, although the direction of bias may differ.

Given the age of maximum incidence of inflammatory bowel disease, aspects such as fertility and pregnancy are especially relevant in the management of these patients. This review article aims to provide a summarized description of the basic concepts that the gastroenterologist should know when assessing an IBD patient with procreative desires and/or who is pregnant. The review has been carried out selecting the most recent and relevant articles on these topics in order to offer updated information on the latest treatments available.

Experimental and behavioral economists, as well as psychologists, commonly assume conditional independence of choices when constructing likelihood functions for structural estimation of choice functions. I test this assumption using data from a new experiment designed for this purpose. Within the limits of the experiment’s identifying restriction and designed power to detect deviations from conditional independence, conditional independence is not rejected. In naturally occurring data, concerns about violations of conditional independence are certainly proper and well-taken (for well-known reasons). However, when an experimenter employs the particular experimental mechanisms and designs used here, the findings suggest that conditional independence is an acceptable assumption for analyzing data so generated.

Stochastic choice, the act of choosing differently in repeated decisions, can be a conscious decision made by individuals who are aware of their inability to make a definitive choice. To examine the prevalence and implications of conscious stochastic choice, we developed a novel method and implemented it in a preference reversal experiment: In each valuation choice between the bet and a varying reference option, subjects could either pay a small cost to select a specific option or opt for a free randomization choice where a computer randomly selects an option. Our findings revealed that the majority of subjects exhibited conscious stochastic choice, and further that their choices were significantly affected by the elicitation procedures.

We argue that a choice that is modified, absent any informational change, is revealed to have been a mistake. In an experiment, we allow subjects to choose from budgets over binary lotteries. To identify mistakes, which we interpret as deviations from an underlying “true” preference, we allow subjects to revise a subset of their initial choices. The set of revised decisions improves under several standard definitions of optimality. These mistakes are prevalent: subjects modify over 75% of their initial choices when given the chance. Subjects make larger mistakes when inexperienced and when choosing over lotteries with small probabilities of winning.

In this study we exploit not only regional but also age and gender variation in exposure to COVID-19 to investigate its impact on risk tolerance. This study is the first to use age and gender variation in exposure to COVID-19, whereas the identification in previous studies relied on regional variation or simple differencing before and after the pandemic. Using a nationally representative household panel survey in Japan, we find that individuals who were exposed to higher risk of COVID-19, measured by the mortality rate, became more risk-tolerant. The result is in line with findings whereby the experience of standout adverse events and the large resulting losses increase individuals’ risk tolerance. However, the effect appears diminished after the vaccine rollout. An analysis using detailed vaccine records indicates that the vaccination offset the increase in risk tolerance due to the mortality risk, especially for individuals with a higher mortality rate for COVID-19. While the literature on this topic has been inconclusive with a few studies reporting insignificant changes in risk tolerance after the pandemic, our result suggests that granular information on exposure to COVID-19 helps identify its impact.